Technical Field
The present invention relates to signal processing, and in particular, acoustic echo cancellation.
Background Art
Acoustic echo is generated when audio signals that are played from a loudspeaker system are picked up by microphones(s). In a speakerphone or audio teleconferencing system, such echo may be attributable to speech signals representing the voices of one or more far end speakers that are played back by the system. In a video game system, acoustic echo may also be attributable to music, sound effects, and/or other audio content produced by a game as well as the voices of other players when online interaction with remote players is supported. Acoustic echo may also be attributable to multi-channel audio being streamed for playback by a mobile device, such as smart phone or tablet. If acoustic echo is not cancelled and/or suppressed, the far end speaker(s) will hear an echo of his or her own voice, which may inhibit natural, continuous conversation. Moreover, in a system that supports speech recognition, voice commands may be misinterpreted with the presence of acoustic echo.
Many schemes to cancel and/or suppress acoustic echo have been proposed. However, these schemes are generally computationally complex, and therefore result in relatively high power consumption. Some acoustic echo cancellation and/or suppression schemes attempt to cancel and/or suppress acoustic echo generated by each of a plurality of channels used to play back audio signals. In accordance with such schemes, as the number of channels used to play back audio signals increases, so does the computational complexity and power consumption.